Adhesive for Polyethylene to Stainless steel

[enginesrus]

It is to help bond black rolled poly pipe to stainless steel fitting. Any idea's what would work best?
I'm thinking a urethane of some sort?

 

[btrueblood]

As usual, give us more details - what pressure? What temperature range? Cycling of both conditions?

The best fittings for this purpose I have seen make a mechanical clamp onto the poly o.d. to resist axial forces, with an elastomer sealing element (rubber oring or similar) in radial compression making the pressure boundary. Look at SharkBite fittings as an example, or JohnGuest push-to-connect fittings. These eventually fail in bending fatigue, with the relatively soft poly tubing being the weak link.

As far as adhesives - nothing comes to mind - polyethylene is a very non-polar, non-reactive substance (i.e. adhesives bond poorly to it). Mechanical devices are more typical, but PE has thermal and tensile properties vastly (orders of magnitude) different than stainless steel. Poly will creep over time under load, i.e. a hose clamp or similar - this slow distortion will cause high strains on the bond line, if one can even be established.

 

[TugboatEng]

Typically, acrylic adhesives are used for the hard to bond plastics.